Fluoridation of Hydroxyapatite Powder by Ammonium Hexafluorosilicate

Abstract

Diamine silver fluoride [AgF: (NH₃)₂AgF] is a unique fluoride solution used clinically in Japan for primary teeth. AgF has been shown to reduce dental caries and dentine hypersensitivity. However, AgF also stains teeth black due to sulfide precipitation and thus is unacceptable for permanent teeth. In the present study, the potential value of ammonium hexafluorosilicate [SiF: (NH₄)₂SiF₆], which has a formula similar to that of AgF but contains no Ag, was studied with respect to its ability to fluoridate apatite. Hydroxyapatite [HAP: Ca₁₀(PO₄)₆(OH)₂] powder was treated with several topical fluoride solutions, i.e. neutral sodium fluoride, acidulated phosphate fluoride (APF) along with AgF and SiF. Following treatment, the HAP powders were analyzed for their fluorine content, crystal -linity changes, and solubility in acidic solution. The highest level of fluoridated HAP [FAP: Ca₁₀(PO₄)₆(OH)xF_2––x] was observed in HAP powder treated with SiF, even though more total fluorine in the form of FAP and CaF₂ was observed in HAP powder samples treated with APF. Presumably as a consequence of this higher level of FAP formation after SiF treatment, the highest level of crystallinity along with the lowest solubility in acidic solution were observed in HAP powder treated with SiF solution. We concluded, therefore, that SiF may have potential value for use as a topical fluoride solution.

Effects of different antibacterial agents on enamel in a biofilm caries model

“…For this esthetic reason, the use of ammonium hexafluorosilicate (AHF) solution, which replaces the silver component with silica, has been suggested for prevention of caries progression (19). Several studies have indicated that AHF treatment does not produce tooth staining; upon application, a large amount of precipitate forms on the tooth surface, and the acidity of the solution causes etching of the hard tissues of the tooth and re-precipitation of calcium and phosphate ions as silica-calcium-phosphate crystals (18)(19)(20)(21). It has been emphasized that the antibacterial activity of AHF solution may be increased when it is used along with several antibacterial agents, such as cetylpyridinium chloride.…”

Effects of ammonium hexafluorosilicate application on demineralized enamel and dentin of primary teeth

“…For prevention of dental caries and treatment of dentin hypersensitivity, ammonium hexafluorosilicate (AHF; (NH 4 ) 2 SiF 6 ) was applied to permanent teeth to overcome tooth discoloration caused by SDF treatment (10). AHF increases the acid resistance of enamel and dentin to almost the same extent as SDF (11).…”

Calcium phosphate biomaterials from marine algae. Hydrothermal synthesis and characterisation

“…It is believed that the use of natural raw materials for the synthesis of HAp enables it to be accepted better by the organism because of its similar physical-chemical characteristics 27,28,35 . Calcium carbonate for the synthesis of calcium phosphates similar to bone can be obtained from several natural sources.…”